Gas-operated firearm.



PATENTED APR. 28, 1903.

A. BURGESS.

GAS OPERATED PIREARM.

APPLICATION FILED Nov. a, 1902.

N0 MODEL.

messes.

" ATENT FFICE..

ANDREW BURGESS, 0F OWEG, NEW YORK.

GAS`OPERATIED FIREARM.

SPECIFICATION forming part of` Letters Patent 110.726,399, dated April 28, 1903.

' Application filed November 3, 1902. Serial No. 129,912. CNo model.) n

To all whom it may concern Be it -known that I, ANDREW BURGEss, a citizen o f the United States,residing at Owego, in the county of Tioga and State of New York, have invented certain new and useful Improvements in Automatic Firearms, of which the following is a specification.

This invention relates to automatic firearms.

The object of theinvention is to producea rearm of lthe class stated in which the opening movement of the barrel is eifected in greater or less degree by the escape of gas from the barrel when the charge is red; also, to eect the closing of the barrel toward the breech by a combined spring-and-leverl action, so that the power` which closes the breech may act most efficiently during the last part of the closing movement; also, to place the firing mechanism under the control of the hand when grasping ithe firearm infiring position and leaving the gun without capacity for firing a cartridge save when the weapon is so held; also, to improve the mechanism by which the weapon may be kept loaded and in safety position. Figure 1 is a central longitudinal section of a magazine-pistol 'according `to the present invention with breech closed. The-cartridgefeeding mechanism is not illustrated. Fig.

- 2 is a similar section of the same firearm with breech open. Fig. 3 is a broken section of a modification of the barrel-returning spring, showing enough of the mechanism to illustrate the points claimed. Fig. 4 is a crosssection on line 4 4, Fig. 2. Fig. 5 is a longitudinal section of modified construction of barrel. g

I have found in practice that with some 4o arms of this class, with s'ome cartridges and 5o rel, said chamber being closed by a shoulder 13 at its front end and by an abutment 14 at the rear end. The abutment 14 may be a part of the frame 2 orbe screwed therein, as shown in Figs. 1 and 2.

When theweaponis red, after the pro jectile has passed the hole in the barrel the gas in the barrelescapes through the hole 10 `the hole 10 in the barrel presses the ring a forward,'the ring` c screwed -in the frame serving as a resistance-piece. When the projectile leaves the gun, the gas in t-he chamber around the barrel is driven back into the barrel by the means which' closes the' barrel and escapes from the muzzle, or if tle barrel be pressed forward Afar enough the gas can escape around the sleeve.- The size of the hole 10 and the distance of said hole from the muzzle are factors in determining the pressure which can be exerted to move the barrel forward.

In the modification Fig. 5 the ring a can b'e screwed to position to partly close hole 10, thus making the device adjustable to admit of the use of more or` less pressure.

When the barrel has been' thrown forward in firing, it is desirable that it close backward toward the breech-plate or recoil-abutment 3 with aL slow initial movement, so that the magazine-feed may operate effectively. To effect this closing movement, I employ a lever 15, having its fulcrum in the frame below the barrel., as at 16, and bearing` so as to press back an ear orears 17 on the sides of the barrel. The ears 17 are preferably provided with antifriction-sleeves 18. The lever 15 is preferably forked at its upper end, so as to bear against ears on both sides of the barrel.

I do not in the present application make any improvement in the mechanism for raising cartridges in the magazine. Such mechanism being old and well \known inl this art it is considered unnecessary and possibly confusing to illustrate the same. The mechanism of my Patent No. 687,448, of November 26, 1901, is well adapted for use in the present invention.

To the lever 15 a push-piece 19 is pivoted,

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and the piston 2O bears against the outer end of said push piece. Said piston-head is pressed back by the coiled spring 21, which is stored in a chamber 22 in the lower part of the fr ame, so as to press back the piston 20. The \piston 2O is merely a.- convenient inert element to convey the pressure of the spring 21 to the lever 15. The lever 15 is so arranged that it stands at a right angle to the axis of the coiled spring 21.when the barrel is closed or nearly closed. When the barrel is in its open or forward position, the spring acts less directly and at a disadvantage and does not start the barrel back with excessive speed. Of course the proportions of parts might be greatly varied from the illustration.

Fig. 3 shows how a fiat spring may be aplplied to a lever to press the barrel back, such arrangement being a wellknown arrangement for operating the hammer of a gun. The particular advantage of the lever connection is that the spring exerts itspower to best advantage when the barrel is nearly closed.

` The lever has a rounded bearing at 16 resting in a corresponding notch in the frame. By taking hold of the projecting ends of the bearing 16 the lever 15 may be taken out of the opening in the bottom of the frame, leaving the barrel free to reciprocate in the frame without resistance from the spring 21.

The barrel is thrown forward by the explo-v sion to open the breech and pressed back by the spring to close the breech, the cartridge being fed in by usual means when the breech is open. The firing is effected by carrying the cartridge forcibly back-against a tiringpoint, the barrel itself serving as a hammer.

The ring pin or point 25 is carried by a lever 26, which is pivoted at 27 Ato the frame, and the body of the lever liesnear the stock 4, being pressed back therefrom by a spring 28.

When the hand of the operator grasps the stock 4in position for firing the gun, the lever is pressed against the stock and the point 25 is held forward, so that it projects through an opening iu the recoil-shield. Then the sudden backward movement of the barrel and the cartridge brings the cap against point 25 and fires the cartridge; but if the lever 26 be free the point 25 does not project or offer sufcient resistance to tire the cartridge. Thus there is small danger of firing the gun accidentally. To still further provid-e a safety device, the trigger 30 has its nose 31 extending forward of its pivot, (see Fig. 3,) and this vextension of the trigger is pressed by the spring 32 with a tendency to enter into the notches 33 34 35 in the barrel. The notch 35 may be called the full-cock notch. When the gun is to be fired the rst time, the barrel is drawn forward by hand until the nose of the trigger enters said notch, as shown in Fig. 2. Then if the handle be firmly grasped and the trigger pulled the nose of the trigger will be drawn out of this notch, the barrel and contained cartridge will be forced back by spring 21, and the cartridge will be fired, carf` rying the barrel forward, and if the trigger be loosened in time the barrel will -be stopped thereby in open position ,but if the trigger be held the firing will continue until the magazine is empty.

When it is desired to leave the gun in position to Iire with a considerable pull, as in a self-cooking pistol, the barrel is moved by hand until the nose of the trigger enters the notch 34, as shown in dotted lines, Fig. 2.. This notch is undercut or has a backward inoline at its front edge, so that when the nose of the trigger enters said notch a strong pull on the trigger will press the barrel a little forward by reason of the cam engagement between the front of the notch 34 and the nose of the trigger. When the trigger has been pulled from the notch, the barrel will fly back and fire the cartridge, as before.

The notch 33 is of the usual half-cock form and further from the rear end of the`barrel and is still more undercut, so that the trigger cannot be pulled out of the notch except by first moving the barrel forward. When-the nose of the trigger is in the notch 33, the weapon is supposed to be in position of safety.

The trigger mechanism illustrated in Figs. 1 and 2 is not herein claimed, being shown and described in my Patent No. 639,106, of February 11, 1902.

It will be observedthat when the barrel is held at full cock, as in Fig. 2, the breech is not fully open, and therefore the cartridge remains partly inclosed by the barrel, so that it may not fall out or become displaced.

1. In automatic firearms, a forwardly-mov-- ing barrel, a gas-receiving chamber, an opening from the barrel to said chamber, and means by which the gas-pressure in the chamber acts to press the barrel forward.

2. In automatic guns, the barrel, a sleeve surrounding the same, an opening fromthe barrel into said sleeve, a fixed abutment irrV the sleeve, and a movable abutment or piston connected to the barrel, all combined.

3. In automatic guns, the perforated barrel, surrounding sleeve having an abutment, and a ring on the barrel within the sleeve acting as a piston to press the barrel forward.

4. In an automatic gun, the perforated barrel, operating gas-chamber, and a screwlring on the barrel to regulate the opening therefrom to said gas-chamber.

5. In an automatic gun, the forwardly-moving barrel, a lever engaging therewith and with the frame so as to be in most effective operating position when the barrel is nearly in its rearmost position, and a spring bearing on said lever. i

6. In an automatic gun, the forwardly-moving barrel, a lever fulcrumed on the frame, and having a bearing against the barrel, and a spring bearing on said lever, combined as described.

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7. In an automatic gun, the frame having a bottom opening, the barrel sliding in said frame, a lever fulcrumed in the frame and bearing against the barrel, and a spring bear# to project and conne said firing-pin forward by the grasp of the hand in firing the gun.

10. A reciprocating barrel arranged to serve as a hammer, a full-cock notch by which the sear automatically holds the barrel cocked, a safety-notch into which the sear may be engaged, said safety-notch being undercut relatively to the sear, and whereby the barrel must be moved forward by a hard trigger pull before its backward movement to fire the gun. In testimony whereof I affix 'ny signature in presence 'of two witnesses. i

' ANDREW BURGESS. Witnesses:

W. A. BARTLETT, CEAS. S. MASON. 

